Study On Low Temperature Paraffin Wax Phase Change Material And Heat Transfer Characteristics

The technology of ocean observation platforms propelled by ocean thermal energy ismainly used in the far-reaching sea observation, and it has a great prospect. It is of greatimportance to monitor ocean climate, research and exploration marine animals,investigation ocean military. Among the technology of ocean observation platformspropelled by ocean thermal energy, the most important part is how to obtain the oceanthermal energy, and the most important part of obtaining ocean thermal energy is the heatexchange material.This paper to solve this problem of selecting phase change material，analyze all kindsof the phase change material, put forward a pros and cons of evaluation criteria aboutphase change material. C15, C16and C17three materials were selected for alternativephase change material, the configuration of two and ternary mixed phase change materialthrough the different proportions of the three materials. Test the alternative materials,volume change rate, the phase transition temperature and other characteristics, and finallyscreen out the solid-liquid phase change material has phase transition temperature in therange of14℃to18℃,greater solid-liquid volume expansion rate, lower latent heat ofphase change.This paper analyzes the paraffinic organic phase change material of a low coefficientof thermal conductivity of the shortcomings. In order to overcome this drawback, thenanother method for enhancing the thermally conductive performance studies, experimentsby the addition of expanded graphite having a high thermal conductivity to improvethermal conductivity of the overall thermal performance. Because the compound heattransfer medium appears instability after adding the expanded graphite, the text analyzesthe instability, and takes the method of adding dispersant and utrasonic vibration, makesthe stable performance of the composite heat transfer medium. Finally, taking further testof the composite phase change materials, researching the additive’s influence on the rateof volume, the phase transition temperature and the latent heat of fusion.The results show that the additive has a little effect on the phase change material, and it can be ignored.The finite element software of Fluent is used to simulate solidification and meltingprocess of phase change material when before and after adding expanded graphite. Afterthe simulation，the change rule and distribution characteristics of temperature，liquidfraction of solidification and melting process have been given. Compare before adding theexpanded graphite with after adding the expanded graphite, it was found that by way ofadding the expanded graphite effectively shorten the time of the phase change process.